1. Field of the Invention
The present invention relates to a method of selecting used secondary batteries, and a method of manufacturing battery packs.
2. Related Art
Battery packs consisting of a plurality of secondary batteries electrically connected to each other have hitherto been used as the power source of electric cars and hybrid cars. Even after an electric car or hybrid car has been disposed of, sometimes, the battery pack that was mounted in the car is still usable. Also, even if the battery pack has been replaced with a new one because of failures in some of the secondary batteries constituting the battery pack, other secondary batteries than those with failures in the replaced old battery pack are still usable. Technologies for avoiding disposal by reusing such still usable ones of secondary batteries that were collected after being used as the power source of electric cars or hybrid cars (hereinafter referred to also as “used secondary battery”) have been proposed in recent years (see, for example, Patent Document 1).